212.4 📌 章末速蚘

  • HAV: ssRNA picornavirus, fecal-oral, never chronic
  • Acute hepatitis with very high AST/ALT (1000+)
  • Prodrome → icterus → recovery course typical 4-8 wk
  • Severe forms: fulminant (1-2% adult, 2-3% ≥ 50 yr), cholestatic, relapsing
  • IgM anti-HAV = acute; IgG = past/vaccine
  • Treatment: supportive; transplant for fulminant
  • Vaccine: inactivated, 2-dose 6-12 mo apart, > 95% efficacy
  • PEP: vaccine + IG within 14 days (IG for high-risk)
  • 2017-2024 USA outbreaks: homeless + IDU + MSM clusters
  • Risk groups: homeless, MSM, IDU, travelers, chronic liver disease
  • Differential: HEV (severe in pregnant, sometimes chronic in immunocompromise)
  • Universal childhood vaccination standard in many countries (USA 2006, Taiwan)